Re: How to optimize the cloning of a disk with a big empty ext3 partition?

From: Gregoire Gentil <gregoire gentil com>

To: "Stephen Samuel (gmail)" <darkonc gmail com>

Cc: ext3-users redhat com

Subject: Re: How to optimize the cloning of a disk with a big empty ext3 partition?

Date: Sat, 20 Jun 2009 17:42:09 -0700

Thanks for the suggestion,
Grégoire
On Fri, 2009-06-19 at 21:39 -0700, Stephen Samuel (gmail) wrote:
> A program like partimage will copy only the sectors that are already
> in use, but it
> requires that the destination partition be at least as big as the
> original (otherwise
> it would be required to relocate used sectors that are near the end of
> the parttition).
>
> The only real way around your problem would be to resize2fs to resize
> the filesystem
> (not the partition) to a bit over 1GB At that point you could safely
> copy only the first
> Gig of the partition (whatever size you changed the filesystem to).
> You could then
> (if you wanted to) resize the filesystem back to fill the partition.
>
> If you just need the data from the partition archived, and don't need
> it to be live,
> then you can just use partimage to dump the used sectors, into a
> file... When you
> need to reconstitute the filesystem, however, partimage will want to
> create a filesystem
> the same size as the original.
>
> On Fri, Jun 19, 2009 at 4:42 PM, Gregoire Gentil <gregoire gentil com>
> wrote:
> Hello,
>
> I need to duplicate a huge number of identical 8GB SD cards on
> which I
> have 1GB of data at the beginning of the disk on various
> partitions and
> then a 7GB ext3 partition which is rather empty (just a few MB
> of data).
>
> The duplicator device enables me to select which sectors I can
> binary-duplicate. I would love to divide by 8 my duplication
> time, by
> duplicating only the first GB and then the beginning of the
> 7GB ext3
> partition.
>
> When I do a mkfs.ext3, I see that the super-block is written
> to various
> locations of the partition which is not good for the
> optimization I
> would like to do.
>
> Anyone can advise how I could optimize my duplication? What
> are my
> options? Would it be the same situation for ext2? Meaning
> where is the
> journal written on the ext3 partition? Is there a single
> version or
> multiple versions?
>
> Thanks in advance for any answer or pointer,
>
> --
> Stephen Samuel http://www.bcgreen.com Software, like love,
> 778-861-7641 grows when you give it away